The invention relates generally to notching or punching systems, and more particularly to automatic notching systems for producing rotor and/or stator laminations from blanks.
Known high speed notching systems for notching slots in blanks, such as circular blanks, to form D.C. motor armatures and/or A.C. rotors, typically require numerous costly and time consuming changeover/set-up operations to properly adjust the notching system each time a different diameter blank is notched. The changeover/set-up costs drastically increase and become prohibitive with conventional notching systems particularly for producers specializing in custom designed A.C. and/or D.C. motors.
Such custom lamination producers must typically produce numerous low volume production lots where each production lot requires the notching of a different diameter blank. Therefore, changeover/set-up operations must be performed more often which results in prohibitive cost increases stemming from substantial machine down time which reduces production capacity and increases labor time dedicated to the change-over/set up operations.
One known type of conventional high speed automatic lamination producing machine uses gear driven arms that are fixedly connected so that both arms move simultaneously during blank actuation. An example of such a machine may be a V&O model 410, manufactured by V&O Press Company, New York. Generally, a blank is removed by one arm from a pre-process mandrel, which contains a stack of blanks, while another fixed arm removes notched blank (lamination) from the notch press and places the blank on a post-process mandrel or carrier. The machine changeover required for different sized blanks is typically started by moving the index spindle of the notch press laterally either in or out relative to the notch press punch and die. Because of this, there is a requirement to re-position both the pre-process mandrel and the post-process mandrels thereby necessitating a stroke adjustment for the arms. Such changeover operations may take as long as 4-5 hours depending on the blank diameter and other factors.
Another type of high speed lamination producing machine utilizes a notch press which requires the index spindle to be adjusted for varying diameter blanks but uses a servo actuated, linear feed mechanism for transporting the blank to the notch press. The index spindle does not retract but remains longitudinally fixed with respect to the laterally adjustable index spindle. A longitudinally movable blank support plate raises to remove the lamination. A simple air cylinder then ejects the lamination from the index spindle to a random location to the side of the machine. An example of the notch press used by such a machine may be a Weingarten model NK 8, manufactured by Muller Weingarten Corporation, Germany.
As with the previously discussed system, a similar problem arises since changeover for a blank of a different size typically requires that the index spindle be either laterally moved in or out in relation to the fixed position of the punch and die as with the above mentioned machine. Therefore, the linear distance from the point that the blank is picked up to the centerline of the index spindle changes and thus requires a change to the distance of the stroke of the linear servo mechanism that feeds the blank to the index spindle. The ejecting mechanism must also be adjusted to accommodate laminations of a different sizes. Furthermore, the ejecting mechanism provides no means of locating the lamination in a precise manner and provides no precise location of the finished lamination therefore such a machine does not stack laminations to form a pre-assembled core as is desirable for high efficiency production processes.
U.S. Pat. No. 4,331,049 discloses yet another automatic notching press which numerically controls a notching press arrangement which includes a multi-armed feed and removing device having a turnstile or turn table which is selectively indexed or rotated so as to convey blanks to various processing systems. The stack unloading station and the rotor stacking station form the first and last processing station and are linked by a conveying device which operates independently of the turntable of the feeding and removing device.
The notch press adjusts for different sized blanks by keeping the index spindle stationary and moving the notching head radially with respect to the blank. The multi-ams are adjustable to transport blanks having different diameters.
However, the transport of the blanks to and from the notching station is facilitated by arms fixed to the turn table so that the arms arcuately move simultaneously to pick up and remove the blank from the pre-process stack and remove the lamination from the notching station. Consequently, such a machine requires the simultaneous pick-up and transfer of blanks between stations and the rate of transport of the blanks between stations is a function of the speed at which the turn table rotates. This rate may be slower than the rate at which the notching machine may notch a blank. Furthermore, the arcuate travel of the arms causes the blanks or laminations to be transported further than may be necessary, thereby slowing down maximum production rates.
Such a system also generally has an expansive size so as to occupy a significant amount of factory floor space and uses a significant amount of complex hardware to achieve the production operation. Therefore, such a system is typically too expensive and bulky for lower volume producers or high volume producers with a wide range of product variations.
To overcome the above problems and for other reasons, there exists a need for a high speed, minimally adjustable notching system which reduces changeover/set-up time and reduces the complexity of conventional lamination producing systems, to accommodate blanks of varying sizes or diameters.